1. Field of the Invention
This invention relates to a fixing structure in which free mounting members are secured to fixed members using screw engagement members.
2. Description of the Prior Art
Openings provided on distributing boards, machines and the like for maintenance purposes are conventionally fixed with covers (mounting members) to seal those openings. To fix a cover on an opening it has been a common practice to insert setscrews (screw engagement members) into female thread portions tapped around the opening on the body (fixed member) of a machine for example, through a plurality of mounting holes provided in the outer circumference of the cover, so that the head portions of the set screws will hold down the surface of the cover.
In the fixing structure mentioned above, the bore diameter of the mounting holes is, needless to say, larger than the outer diameter of the set screws' male thread portions. At the same time, the bore diameter of the mounting holes is generally made smaller than the head portions of the setscrews. Because of this, when the cover is removed from the opening of the machine to do maintenance for example, all of the setscrews should be completely pulled out from the female thread portions.
This tends to make the removal of the cover take time and to cause a risk of losing the setscrews which have been once pulled out.